Motor driving device and abnormal heat generation detecting method for motor driving device

Abstract

A motor driving device includes a heat sink, a rectifier provided on the heat sink and configured to rectify an AC voltage supplied from an AC power supply to a DC voltage, a charging resistor provided on the heat sink and configured to be used for charging a smoothing capacitor for smoothing the DC voltage rectified by the rectifier, and a temperature sensor with which the charging resistor is provided.

What is claimed is: 
     
       1. A motor driving device for driving a motor, comprising:
 a heat sink; 
 a rectifier provided on the heat sink and configured to rectify an AC voltage supplied from an AC power supply to a DC voltage; 
 a smoothing capacitor configured to smooth the DC voltage rectified by the rectifier; 
 a charging resistor provided on the heat sink and configured to be used for charging the smoothing capacitor during an initial charging period before start of driving the motor; 
 a temperature sensor with which the charging resistor is provided; and 
 a controller configured to determine that at least one of the rectifier or the charging resistor is abnormally generating heat when a temperature detected by the temperature sensor after a lapse of the initial charging period is equal to or higher than a first threshold, and then stop supply of the AC voltage to the rectifier. 
 
     
     
       2. The motor driving device according to  claim 1 , further comprising a notifier configured to issue a notification that abnormal heat generation occurs. 
     
     
       3. The motor driving device according to  claim 2 , further comprising an input power detector configured to detect an input power supplied from the AC power supply to the rectifier, wherein:
 the controller is configured to determine that the charging resistor is abnormally generating heat when the temperature is equal to or higher than the first threshold and the input power is less than a second threshold; and 
 the notifier is configured to issue a notification that the charging resistor is abnormally generating heat. 
 
     
     
       4. The motor driving device according to  claim 3 , further comprising a capacitor voltage detector configured to detect a capacitor voltage across the smoothing capacitor, wherein:
 the controller is configured to determine that the rectifier is abnormally generating heat when the temperature is equal to or higher than the first threshold, the input power is equal to or higher than the second threshold and the capacitor voltage is equal to or higher than a third threshold; and 
 the notifier is configured to issue a notification that the rectifier is abnormally generating heat. 
 
     
     
       5. The motor driving device according to  claim 4 , wherein:
 the controller is configured to determine that the capacitor voltage is low when the temperature is equal to or higher than the first threshold, the input power is equal to or higher than the second threshold and the capacitor voltage is less than the third threshold; and 
 the notifier is configured to issue a notification that the capacitor voltage is low. 
 
     
     
       6. The motor driving device according to  claim 1 , further comprising a power supply switch provided between the AC power supply and the rectifier, wherein the controller is configured to stop the supply of the AC voltage to the rectifier by setting the power supply switch in an open state. 
     
     
       7. The motor driving device according to  claim 1 , further comprising a charging switch connected in parallel with the charging resistor, wherein the controller is configured to set the charging switch in an open state during the initial charging period and close the charging switch after a lapse of the initial charging period. 
     
     
       8. An abnormal heat generation detecting method for a motor driving device for driving a motor, wherein the motor driving device includes:
 a heat sink; 
 a rectifier provided on the heat sink and configured to rectify an AC voltage supplied from an AC power supply to a DC voltage; 
 a smoothing capacitor configured to smooth the DC voltage rectified by the rectifier; 
 a charging resistor provided on the heat sink and configured to be used for charging the smoothing capacitor during an initial charging period before start of driving the motor; and 
 a temperature sensor with which the charging resistor is provided, 
 the method comprising: 
 a first step of stopping supply of the AC voltage to the rectifier when a temperature detected by the temperature sensor after a lapse of the initial charging period is equal to or higher than a first threshold, and 
 a second step of issuing a notification that abnormal heat generation occurs. 
 
     
     
       9. The abnormal heat generation detecting method for the motor driving device according to  claim 8 , wherein:
 the first step determines that the charging resistor is abnormally generating heat when the temperature is equal to or higher than the first threshold and an input power supplied from the AC power supply to the rectifier is less than a second threshold; and 
 the second step issues a notification that the charging resistor is abnormally generating heat. 
 
     
     
       10. The abnormal heat generation detecting method for the motor driving device according to  claim 9 , wherein:
 the first step determines that the rectifier is abnormally generating heat when the temperature is equal to or higher than the first threshold, the input power is equal to or higher than the second threshold, and a capacitor voltage across the smoothing capacitor is equal to or higher than a third threshold; and 
 the second step issues a notification that the rectifier is abnormally generating heat. 
 
     
     
       11. The abnormal heat generation detecting method for the motor driving device according to  claim 10 , wherein:
 the first step determines that the capacitor voltage is low when the temperature is equal to or higher than the first threshold, the input power is equal to or higher than the second threshold, and the capacitor voltage is less than the third threshold; and 
 the second step issues a notification that the capacitor voltage is low.